/*	$OpenBSD: sleep.c,v 1.29 2020/02/25 15:46:15 cheloha Exp $	*/
/*	$NetBSD: sleep.c,v 1.8 1995/03/21 09:11:11 cgd Exp $	*/

/*
 * Copyright (c) 1988, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "compat.h"
#include <sys/time.h>

#include <ctype.h>
#include <err.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <string.h>

void alarmh(int);
void usage(void);

int main(int argc, char *argv[]) {
  setprogname(argv[0]);
  struct timespec rqtp;
  time_t t;
  char *cp;
  int ch, i;

  signal(SIGALRM, alarmh);

  while ((ch = getopt(argc, argv, "")) != -1) {
    switch (ch) {
    default:
      usage();
    }
  }
  argc -= optind;
  argv += optind;

  if (argc != 1)
    usage();

  memset(&rqtp, 0, sizeof(rqtp));

  /* Handle whole seconds. */
  for (cp = argv[0]; *cp != '\0' && *cp != '.'; cp++) {
    if (!isdigit((unsigned char)*cp))
      errx(1, "seconds is invalid: %s", argv[0]);
    t = (rqtp.tv_sec * 10) + (*cp - '0');
    if (t / 10 != rqtp.tv_sec) /* overflow */
      errx(1, "seconds is too large: %s", argv[0]);
    rqtp.tv_sec = t;
  }

  /*
   * Handle fractions of a second.  The multiplier divides to zero
   * after nine digits so anything more precise than a nanosecond is
   * validated but not used.
   */
  if (*cp == '.') {
    i = 100000000;
    for (cp++; *cp != '\0'; cp++) {
      if (!isdigit((unsigned char)*cp))
        errx(1, "seconds is invalid: %s", argv[0]);
      rqtp.tv_nsec += (*cp - '0') * i;
      i /= 10;
    }
  }

  if (rqtp.tv_sec || rqtp.tv_nsec) {
    if (nanosleep(&rqtp, NULL) == -1)
      err(1, "nanosleep");
  }

  return 0;
}

void usage(void) {
  fprintf(stderr, "usage: %s seconds\n", __progname);
  exit(1);
}

/*
 * POSIX.1 says sleep(1) may exit with status zero upon receipt
 * of SIGALRM.
 */
void alarmh(int signo) {
  /*
   * Always _exit(2) from signal handlers: exit(3) is not
   * generally signal-safe.
   */
  _exit(0);
}
